Rain water seeps through doors and windows for a hundred and one reasons. In order to prevent this, rain water deflectors, or door and window hoods are installed.
Even well built doors loose their shape in time, and they start allowing water to go through. Apatures in wood and in P.V.C. get warped, while weather stripping on aluminium doors and windows often dries up and gets detached. For one reason or another water gets through.
Multitrade supplies rain water deflectors in aluminium, zinc plated steel, and in stainless steel. These are available in different widths, and numerous lengths.
They are ready to pick off the shelve. You just walk into the store, find the required size, and go back home to stop the leaking rain water, by fixing the rain water deflector.